Proface LT3300 - 5.7 All-in-One HMI" - Manual (Page 12)

12
3. Grounding Cautions
• Be sure to create an exclusive ground for
the Power Cord’s FG terminal. Use a
grounding resistance of 100
Ω, a wire of
2mm
2
or thicker, or your country’s applica-
ble standard.
• The SG (signal ground) and FG (frame
ground) terminals are connected internally
in the LT unit.
When connecting the SG line to another
device, be sure that the design of the sys-
tem/connection does not produce a short-
ing loop.
• The grounding wire should have a cross
sectional area greater than 2mm
2
. Create
the connection point as close to the LT unit
as possible, and make the wire as short, as
possible. When using a long grounding
wire, replace the thin wire with a thicker
wire, and place it in a duct.
4. Input/Output Signal Line Cautions
• All LT Input and Output signal lines must
be separated from all operating circuit
(power) cables.
• If this is not possible, use a shielded cable
and ground the shield.
5. Wiring Precautions
• To help prevent noise and interference
problems, separate all control, communica-
tion and power lines by placing them in a
separate ducts.
If different wires must be placed in the same
duct, separate them with an earthed/grounded
divider.
• If the lines cannot be separated, use
shielded lines and create a ground from the
shield line.
• Use noise-reducing external wiring
methods to increase overall system
reliability.
• To prevent power surges or noise inter-
ference, use ducts to separate all DC I/
O or current circuit wires from commu-
nication cables.
LT unit
Other
Equipment
Exclusive Grounding
(BEST)
LT unit
Other
Equipment
Common Grounding (OK)
LT unit
Other
Equipment
Common Grounding
(Not OK)
Duct for I/O Sig-
nal Lines Duct for Control
Lines Duct for Power
Lines
I/O Signal
Lines Control
Lines Power
Lines
Grounded
Separators
Duct (non-
conducting
resin/plas-
tic)
Earth/Ground